Descriptions

Acute toxicity bioassays (96-hr TL₅₀) were employed to determine
the tolerance of coho salmon (Oncorhynchus kisutch) to inorganic
chloramines at the alevin (yolk sac fry), yolk absorption, and early
juvenile life stages. Any influence of changes in temperature, pH,
and total alkalinity on the tolerance of juvenile coho for chloramines
was also investigated.
The least tolerant stage occurred shortly after yolk absorption.
No change in juvenile coho was found when temperature was increased
from 10.8 to 15.0 C. Increasing alkalinity from 135 to 320 mg/l was
not shown to affect tolerance of the juvenile stage. Increasing pH
from 7.0 to 7.5 apparently did not change tolerance at this stage,
but an increase from 7.5 to 8.1 resulted in a significant decrease
in tolerance.